Seed coating composition

ABSTRACT

COMPOSITION FOR TREATING SEEDS COMPRISING AN AQUEOUS EMULSION OF A SUBSTANTIALLY WATER-SOLUBLE NEUTRALIZED COPOLYMER OF AN A,B-UNSATURATED MONOCARBOXYLIC ACID AND A LOWER ALKYL ACRYLATE AND A CROSSLINKED COPOLYMER OF VINYL ACETATE AND A LOWER ALKYL ACRYLATE. THESE COMPOSITIONS ENHANCE THE GERMINATION OF THE SEEDS.

Patented Aug. 10, 1971 3,598,565 SEED COATING COMPOSITION Thomas M.Graves, 4011 Roosevelt Ave., Richmond, Calif. 94805 No Drawing. FiledJuly 30, 1968, Ser. No. 748,617 Int. Cl. A0111 /00; A01c 1/06 US. C].7177 9 Claims ABSTRACT OF THE DISCLOSURE Composition for treating seedscomprising an aqueous emulsion of a substantially water-solubleneutralized copolymer of an cap-unsaturated monocarboxylic acid and alower alkyl acrylate and a crosslinked copolymer of vinyl acetate and alower alkyl acrylate. These compositions enhance the germination of theseeds.

FIELD OF INVENTION This invention relates to a novel, water-soluble seedcoating composition comprising a homogeneous mixture of two copolymers.

INVENTION BACKGROUND It is common to treat seeds with hard resins toprotect the seed from damage during handling. Such coatings also affordthe advantages of protecting the seeds from pest attack and smoothingthe seed surface to make planting easier. In order to improve the seedgermination, or the germination rate, plant nutrients are incorporatedinto the hard resin coating. Pesticides may be incorporated to furtherprotect the seed from pest attack.

INVENTION DESCRIPTION A unique seed coating composition has now beendiscovered which not only provides a protective coating for the seed,but also enhances its germination rate and the viability of the emergingseedling. This enhancement occurs without incorporating plant nutrientsinto the coating composition.

The novel coating composition of this invention comprises an aqueousemulsion of two copolymers. One copolymer is a substantiallywater-soluble neutralized copolymer of an a,B-unsaturated monocarboxylicacid and a lower alkylacrylate. The mol proportion of neutralized acidto acrylate in these copolymers will usually range from 40:1 to about1:1, preferably 25:1 to 4:1.

The a,B-unsaturated monocarboxylic acid of the copolymer contains 3 toabout 6 carbon atoms. Such acids include acrylic acid, rx-methylacrylicacid, crotonic acid, u-rnethylcrotonic acid and the like. Acrylic acidand amethylacrylic acid are preferred. The lower alkylacrylate of thecopolymer contains 4 to about .10 carbon atoms; with the acid (acrylate)moiety contributing 3 to about 6 carbon atoms to the total carbonnumber. Examples of such acrylates are methylacrylate, ethylacrylate,isopropylacrylate, methyl-a-methylacrylate, ethyl-wmethylacrylate,amyl-a-methylacrylate, hexyl-a-methylacrylate, methylcrotonate,butylcrotonate, methyl-a-methylcrotonate and the like. The lower alkylesters of acrylic acid and a-methylacrylic acid are preferred.

The acid portion of the copolymer is neutralized with an alkaline earthmetal, alkali metal or ammonium base. After neutralization the copolymerwill have a pH in the range of about 5.5 to 8.5.

The second copolymer is a polyvinylacetate crosslinked with a smallamount of lower alkylacrylate. The amount of lower alkylacrylate in thiscrosslinked copolymer will usually be not greater than 25% by weight.Usually it will be about 0.3 to 5% by weight of the second copolymer.

The lower alkylacrylate of the second copolymer contains 4 to about 10carbon atoms; with the acid moiety contributing 3 to about 6 carbonatoms to the total carbon number. Examples of these acrylates aremethylacrylate,

ethylacrylate, hexylacrylate, methyl-u-methyl acrylate,butyl-u-methylacrylate; methylcrotonate, ethyl-u-methylcrotonate and thelike. The methyl esters of acrylic acid and a-methylacrylic acid arepreferred.

As used herein the term lower alkyl means alkyl of 1 to 6 carbon atoms.

The two copolymers usually comprise about 10 to 60% by weight of theaqueous emulsion. The weight ratio of the crosslinked polyvinylacetatecopolymer to the 11,5- unsaturated acid-acrylate copolymer will be about1:2 to about 1:10, preferably 1:3 to 1:5. The composition of thisinvention also contains one or more nonionic emulsifiers in amountsnormally ranging between 0.5 to 5% by weight of the composition. Typicalnonionic emulsifiers are the polyethenoxy ethers and esters such as thecondensation products of fatty acids, alcohols or phenolics withethylene and/or propylene oxide; esters of fatty acids and polyols;condensation products of alkylene oxides and thiols; polyoxyalkyleneesters of phosphoric acid and polyhydroxy compounds such as sucrose,dextrine and the like. Such emulsifiers are described in Surface ActiveAgents and Detergents, Schwartz, Perry and Berch, Interscience (1958).

The emulsion may also contain pigments, pesticides and other additives.Plant nutrients may also be added; but, as indicated previously,excellent germination is effected without them.

According to this invention, the seeds are coated with theabove-described composition such that when the seeds dry they arecovered uniformly with a homogenous mixture of two copolymers. Thecoating is substantially watersoluble, hard-usually at least 3H pencilhardness-exceptionally smooth and not sticky. This coating may beapplied to the seed surface by spraying or brushing. Alternatively, theseeds may be tumbled or dipped into the invention composition. Thethickness of the resulting seed coating will vary with the type of seed.Usually it will range between about 0.001 and about 5 mils, preferably0.01 to 2 mils.

The coating of this invention has been used with a variety of seedsincluding corn, peas, beans, wheat, sorghum, cotton, sunflower and othergrain seeds. The coatings on these seeds cause them to generallygerminate faster and enhance the seedling growth and viability.

EXAMPLES The compositions of this invention and their physiologicalefi'ects on seeds are illustrated by the following examples. Theseexamples are intended to illustrate the invention. described herein andare not intended to limit it in any manner. Unless indicated otherwise,percentages are by weight.

Example 1 A resin seed coating of this invention was prepared by mixing15.5 g. of a 40% aqueous emulsion of a copolymer comprising vinylacetate crosslinked with a small amount of lower alkyl methacrylate(sold under the name Nacrylic 25-2813) and 84.5 g. of a 30% aqueoussolution of a neutralized acrylic acid methyl methacrylate copolymer(sold under the name Joncryl 3.88 g. of this mixture was added to 5.15g. of an aqueous solution of 1 g. of N-(trichloromethylthio)tetrahydrop'hthalamide seed protectant (sold as Orthocide 75 SeedProtectant). The mixture was agitated for five minutes with a creamysuspension resulting.

g. of seed corn was placed in a 16 oz. jar. 1 ml. of the above-describedresin seed coating was placed on top of the corn. The bottle was sealedand swirled for 2 3 minutes. The seeds were spread out and allowed todry for minutes.

The resulting seed coating was uniform, non-dusty and had a thickness ofabout 0.2 ml. The coating was completely soluble in water.

The seeds were germinated in dishes lined with filter paper and alongwith comparison seeds treated only with the N-(trichloromethylthio)tetrahydrophthalirnide seed protectant and water at the same rate.

The seeds were watered with ml. of water initially. At the end of 2 and5 days the hypocotyl and epicotyl growths were measured in millimetersand compared. Based on these measurements the resin treated seeds showedabout an 18% better growth than the comparison seeds after 2 days andabout a 31% better growth after 5 days.

The root systems were carefully clipped from each seed and weighed. Theresin treated seed clippings showed a weight increase of about 17% after5 days, over the comparison seed clippings.

Example 2 100 g. of bean seeds was placed in a 16 oz. jar. 1 ml. of theresin seed coating of Example 1 was placed on top of the beans. Thebottle was sealed and swirled for 2 minutes. The seeds were spread outand allowed to dry for 5 minutes.

The resulting seed coating was uniform, non-dusty and had a thickness ofabout 0.4 ml. The coating was completely soluble in water. These beanseeds and comparison bean seeds were germinated as in Example 1. At theend of 2 and 5 days the root systems were measured in millimeters. Thesemeasurements showed the resin treated seeds had about 50% better growththan the comparison seeds after 2 days and about 50% better growth after5 days. The resin treated seed clippings showed a weight increase ofabout 47% after 5 days over the comparison seed clippings.

Example 3 100 g. of wheat seed was placed in a 16 oz. jar. 1 m1. of theresin seed coating of Example 1 was placed on top of the wheat. Thebottle was sealed and swirled for 2 minutes. The seeds were spread outand allowed to dry for 5 minutes. The resulting seed coating was uniformand had a thickness of about 0.05 ml. The coating was completely solublein water.

These seeds and comparison seeds were germinated as in Example 1. At theend of 5 and 10 days hypocotyl and epicotyl growths were measured inmillimeters. These measurements showed that the resin treated seeds hadabout 10% better growth than the comparison seeds after 5 days and about11% better growth after 10 days.

As will be evident to those skilled in the art, various modifications onthis invention can be made or followed, in the light of the foregoingdisclosure and discussion, without departing from the spirit or scope ofthe disclosure or from the scope of the following claims.

I claim:

1. Composition for treating seeds comprising an aqueous emulsion of 10to 60 weight percent of (1) a substantially water-soluble neutralizedcopolymer of an afiunsaturated monocarboxylic acid of 3 to about 6carbon atoms and a lower alkyl acrylate of 4 to about 10 carbon atoms,and (2) a crosslinked copolymer of vinyl acetate and a lower alkylacrylate of 4 to about 10 carbon atoms, the weight ratio of thecrosslinked copolymer to the watersoluble neutralized copolymer being inthe range of about 1:2 to about 1:10.

2. The composition of claim 1 wherein the n p-unsaturated monocarboxylicacid is acrylic acid or a-methylacrylic acid, the lower alkyl acrylateof the substantially water-soluble copolymer is a lower alkyl ester ofacrylic 4 acid or a lower alkyl ester of a-methylacrylic acid and thelower alkyl acrylate of the crosslinkedcopolymer is the methyl ester ofacrylic acid or the methyl ester of amethylacrylic acid.

*3. The composition of claim 1 wherein the mol proportion of ati-unsaturated monocarboxylic acid to lower alkyl acrylate of thesubstantially water-soluble copolymer is in the range of 40:1 to about1:1 and the amount of lower alkyl acrylate in the crosslinked copolymeris less than 25% by weight.

4. The composition of claim 1 wherein the mol proportion oftarp-unsaturated monocarboxylic acid to lower alkyl acrylate of thesubstantially water-soluble copolymer is in the range of 25:1 to 4:1 andthe amount of lower alkyl acrylate in the crosslinked copolymer is inthe range of about 0.3 to 5% by weight.

5. The composition of claim 1 wherein the weight ratio of thecrosslinked copolymer to the substantially water-soluble neutralizedcopolymer is in the range of 1:3 to 1:5.

6. Method for enhancing the germination of seeds and the viability ofseedlings of said seeds which comprises coating said seeds with asubstantially water-soluble homogeneous resin mixture of -(1) asubstantially watersoluble neutralized copolymer of an0a,,B-llI1SE1tllI'3t6d monocarboxylic acid of 3 to about 6 carbon atomsand a lower alkyl acrylate of 4 to about 10 carbon atoms, and (2) acrosslinked copolymer of vinyl acetate and a lower alkyl acrylate of 4to about 10 carbon atoms, the weight ratio of the crosslinked copolymerto the water-soluble neutralized copolymer being in the range of about1:2 to about 1:10. 1

7. The method of claim 6 in which the n p-unsaturated monocarboxylicacid is acrylic acid or u-methylacrylic acid, the lower alkyl acrylateof the substantially watersoluble copolymer is a lower alkyl ester ofacrylic acid or a lower alkyl ester of a-methylacrylic acid and thelower alkyl acrylate of the crosslinked copolymer is the methyl ester ofacrylic acid or the methyl ester of amethylacrylic acid.

8. Composition for treating seeds comprising an aqueous emulsion of10-60 weight percent of 1) a substantially water-soluble neutralizedcopolymer of an a, ,B-unsaturated monocarboxylic acid of 3 to about 6carbon atoms and a lower alkyl acrylate of 4 to about 10 carbon atomswith the acid moiety of the lower alkyl acrylate contributing 3 to 6carbon atoms of the total number, the mole portion of the0a,,6-11I1S21t11l21t8d monocarboxylic acid to lower alkyl acrylate beingin the range of about 40:1 to about 1:1, and (2) a crosslinked copolymerof vinyl acetate and a lower alkyl acrylate of 4 to about 10 carbonatoms with the acid moiety of the lower alkyl acrylate contributing 3 to6 carbon atoms of the total number, the amount of lower alkyl acrylatein the crosslinked copolymer being less than 25 weight percent, theweight ratio of the crosslinked copolymer to the water-solubleneutralized copolymer being in the range of 1:2 to about 1:10.

9. The composition of claim 8 containing a nonionic emulsifier in theamount of 0.5 to 5 weight percent.

References Cited UNITED STATES PATENTS 3,113,399 12/1963 Eversole et al4757.6 3,212,967 10/1965 McFadden et a1 424-78 LEWIS GOTTS, PrimaryExaminer C. L. MILLS, Assistant Examiner U.S. Cl. X.R.

7l-Dig. 1; 47--57.6

